title: Multicenter validation of spin-density projection-assisted R2-MRI for the noninvasive measurement of liver iron concentration.
abstract: OBJECTIVE
  Magnetic resonance imaging (MRI)-based techniques for assessing liver iron concentration (LIC) have been limited by single scanner calibration against biopsy. Here, the calibration of spin-density projection-assisted (SDPA) R2-MRI (FerriScan®) in iron-overloaded β-thalassemia patients treated with the iron chelator, deferasirox, for 12 months is validated.
  
  
  METHODS
  SDPA R2-MRI measurements and percutaneous needle liver biopsy samples were obtained from a subgroup of patients (n = 233) from the ESCALATOR trial. Five different makes and models of scanner were used in the study.
  
  
  RESULTS
  LIC, derived from mean of MRI- and biopsy-derived values, ranged from 0.7 to 50.1 mg Fe/g dry weight. Mean fractional differences between SDPA R2-MRI- and biopsy-measured LIC were not significantly different from zero. They were also not significantly different from zero when categorized for each of the Ishak stages of fibrosis and grades of necroinflammation, for subjects aged 3 to <8 versus ≥8 years, or for each scanner model. Upper and lower 95% limits of agreement between SDPA R2-MRI and biopsy LIC measurements were 74 and -71%.
  
  
  CONCLUSIONS
  The calibration curve appears independent of scanner type, patient age, stage of liver fibrosis, grade of necroinflammation, and use of deferasirox chelation therapy, confirming the clinical usefulness of SDPA R2-MRI for monitoring iron overload.
authors.affiliation: Biomedical Physics, School of Physics, The University of Western Australia, Crawley, Australia.
authors.forename: Tim G
authors.initials: TG
authors.lastname: St Pierre
authors.forename: Amal
authors.initials: A
authors.lastname: El-Beshlawy
authors.forename: Mohsen
authors.initials: M
authors.lastname: Elalfy
authors.forename: Abdullah
authors.initials: A
authors.lastname: Al Jefri
authors.forename: Kusai
authors.initials: K
authors.lastname: Al Zir
authors.forename: Shahina
authors.initials: S
authors.lastname: Daar
authors.forename: Dany
authors.initials: D
authors.lastname: Habr
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kriemler-Krahn
authors.forename: Ali
authors.initials: A
authors.lastname: Taher
mesh_terms: D000293:Adolescent; D000328:Adult; D001565:Benzoates / Q000627:therapeutic use; D001707:Biopsy, Needle; D002138:Calibration; D015913:Chelation Therapy / Q000379:methods; D002648:Child; D002675:Child, Preschool; D000077588:Deferasirox; D005260:Female; D006801:Humans; D007501:Iron / Q000378:metabolism; D007502:Iron Chelating Agents / Q000627:therapeutic use; D019190:Iron Overload / Q000175:diagnosis* / Q000188:drug therapy; D008099:Liver / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011446:Prospective Studies; D016896:Treatment Outcome; D014230:Triazoles / Q000627:therapeutic use
chemical_list: D001565:Benzoates; D007502:Iron Chelating Agents; D014230:Triazoles; D007501:Iron; D000077588:Deferasirox
keywords: ESCALATOR; biopsy; deferasirox; iron overload; β-thalassemia